"WebGL is basically an initiative to bring 3D graphics into web browsers natively, without having to download any plugins. This is achieved by adding a few things to HTML5, namely, defining a JavaScript binding to OpenGL ES 2.0 and letting you draw things into a 3D context of the canvas element." Also see the press release for more details.

Seriously, IE users always end up with so many ridiculous toolbars and other forms of malware - let's give them an ActiveX plugin that embeds an entire modern browser, so we can stop being required to support IE6!